The perception that there is great risk in smoking marijuana is decreasing among youth.

In 2012, 44.1 percent of 12th graders said there was a great risk in smoking marijuana regularly. These numbers had been steadily declining over the last six years.

Is it Addictive? Marijuana is often thought to not be addictive. However, marijuana—not alcohol— dependence is the number one reason why youth in the U.S. seek substance-abuse treatment. Youth are more likely than adults to become addicted to marijuana. About 4.5 million people in the U.S. meet clinical criteria for marijuana dependence. THC stimulates brain cells to release the chemical dopamine, which creates a euphoric feeling and can lead to a physical addiction. Similar to tobacco withdrawal, people trying to quit marijuana use report irritability, sleeping difficulties, craving, and anxiety.

What is Marijuana? Marijuana is a drug made from the dry, shredded parts of the Cannabis sativa hemp plant. It is usually smoked in hand-rolled cigarettes called joints, in pipes, or in water pipes called bongs. It is also smoked in blunts, which are hollowed-out cigars filled with a mixture of tobacco and marijuana. Marijuana contains a potent chemical called delta-9- tetrahydrocannabinol, more commonly known as THC. It’s very similar to chemicals that the brain naturally produces, and disrupts the function of these chemicals in the brain. Marijuana today is more potent than marijuana of past decades. For a long time THC levels averaged 2.3 percent of the known compounds in marijuana. Today, average THC levels are higher than 8 percent and can go up to 35 percent in medical marijuana.

Tobacco vs. Marijuana

Like tobacco smoke, marijuana smoke contains cancer-causing chemicals. There are 33 cancer-causing chemicals contained in marijuana. Marijuana smoke also deposits tar into the lungs. In fact, when equal amounts of marijuana and tobacco are smoked, marijuana deposits four times more tar into the lungs. This is because marijuana joints are un-filtered and often more deeply inhaled than cigarettes. Marijuana smoke is also an irritant to the lungs, and frequent marijuana smokers can have many of the same respiratory problems experienced by people who smoke tobacco. These include coughing and on most days, wheezing, bronchitis, and greater risk of lung infection.

Other Health Effects

Marijuana has many effects on the brain. It impairs short-term memory and motor coordination; slows reaction time; alters mood, judgment and decision-making; and in some people can cause severe anxiety or loss of touch with reality. Because of these effects, marijuana use more than doubles a driver’s risk of being in an accident. Marijuana also affects the heart. The heart rate is raised 20-100 percent shortly after smoking, an effect which can last up to 3 hours and put users at an increased risk of heart attack. Marijuana use can affect the general quality of the user’s life as well. Daily marijuana users generally report poorer mental and physical health, more relationship problems and lower academic and career success compared to their peers.

Can Marijuana be Medicine?

While TCH has been approved by the FDA as a drug, smoking marijuana has not. This is because there’s no proof yet that the benefits of smoking marijuana outweigh the risks.

Youth and Marijuana

Marijuana use is particularly harmful to youth since the part of the brain that craves pleasure matures earlier than the area that controls our ability to understand risks and consequences. A national study by Monitoring the Future showed that in 2012, 6.5 percent of 12th graders reported using marijuana daily. Marijuana is highly accessible, especially to older teenagers. In 2012, 82 percent of 12th graders reported marijuana as being fairly easy or very easy to get. Studies show that as availability increases, perception of harm decreases.